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Cdc2-Cyclin B–Induced G2 to M Transition in Perch Oocyte Is Dependent on Cdc251

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Title Cdc2-Cyclin B–Induced G2 to M Transition in Perch Oocyte
Is Dependent on Cdc251
 
Creator Basu, Dipanjan
Navneet, A.K.
Dasgupta, Subrata
Bhattacharya, Samir
 
Subject Cell Biology & Physiology
 
Description The G2 to M phase transition in perch oocytes is regulated
by maturation promoting factor (MPF), a complex of Cdc2 and
cyclin B. In Anabas testudineus, a fresh water perch, 17a,20bdihydroxy-
4-pregnen-3-one, the maturation inducing hormone
(MIH), induced complete germinal vesicle breakdown (GVBD)
of oocytes at 21 h. An unusual cyclin, p30 cyclin B, has been
identified in oocyte extract using both monoclonal and polyclonal
antibodies. Surprisingly, Cdc2 could not be identified, although
a Northern blot with Cdc2 cDNA demonstrated expression
of the gene. Purification of MPF through an immunoaffinity
column followed by SDS-PAGE showed three proteins, Cdc2, cyclin
B, and a 20 kDa fragment, indicating earlier failure in immunodetection
may be due to the interference by this fragment.
In uninduced oocytes, p30 cyclin B was present, and its expression
was increased by MIH. MIH increased p30 cyclin B accumulation
at 3 h, a high level which was maintained between 9
and 21 h, but an effective increase in GVBD and H1 kinase
activation could only be observed between 15 and 21 h. This
delay in active MPF formation was found to be related to the
activation of Cdc25, phosphorylation of which was detected at
12 h, and a substantial increase occurred during 15–18 h. Sodium
orthovanadate, a tyrosine phosphatase inhibitor, inhibited
H1 kinase activity and GVBD, suggesting the requirement of
Cdc25 activity in MPF activation. Our results show occurrence
of pre-MPF in uninduced oocytes and its conversion to active
MPF requires dephosphorylation by Cdc25, the existence of
which has not yet been shown in fish.
 
Date 2004
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/520/1/BIOLOGY_OF_REPRODUCTION%2C_71(_3)%2C__894%2D900_[24].pdf
Basu, Dipanjan and Navneet, A.K. and Dasgupta, Subrata and Bhattacharya, Samir (2004) Cdc2-Cyclin B–Induced G2 to M Transition in Perch Oocyte Is Dependent on Cdc251. Biology of Reproduction, 71 (3). pp. 894-900.
 
Relation http://dx.doi.org/10.1095/biolreprod.104.029611
http://www.eprints.iicb.res.in/520/